Drying oven



A ug.43', 1943. N. J. GREENE ETAL 2,325,950

DRYING OVEN Filed May '7, 1940 5 Sheets-Sheet 1 129 BY 60 c wilfl a g- 1943. N. J. GREENE ETAL DRYING OVEN Filed May '7 5. Sheets-Sheet 6 mm M Ma I l nuwhuw 1| ETw flwv m W 6 m u n M m I e m m w w M m M W u E n a w so? ma 2;

Q 3 I 3 m3 Jul ATTORNEY i Aug. 3, 1943.

N.J.GREENE ETAL Filed May 7. 1940 DRYING OVEN 5 Sheets-Sheet 5 g- 3, 1943- N. J.'GREENE ETAL4 2,325,950

DRYING OVEN Filed May 7, 1940 s Sheets-Sheet 4 Patented Aug. 3, 1943 name OVEN Nathan J. Greene, Worthington, and George C.- Reese, Columbus, Ohio, assignors to National Electric Coil Company, Columbus, Ohio, a corporation of West Virginia Application May 7, 1940, Serial No. 333,804 I '1 Claims.

The present invention relates to ovens and more particularly to ovens for drying coatin material on wires.

One of the objects of the present invention is to provide an oven formed in two sections relatively movable to one another for forming a gap and to provide mechanism for bodily or translatably moving the oven and for simultaneously opening and closing the gap so that when the oven is moved in one direction the gap is opened to receive the wire, and is then closed after the wire is in the oven, and, when the oven is moved in the opposite direction the gap is opened for the purpose of removing the oven from about the wire and is then reclosed after the oven is moved away from the wire.

Still another object is to provide, in connection with a wire treating apparatus that affects the length of the wire, a spool for receiving the treated wire and a device for guiding the wire through the apparatus, which device is automatically movable in the direction of the change in length of the wire for maintaining a substantially constant tension on the wire and providing slack in the wire when the apparatus is shut down and prior to shrinkage of the wire.

Still another object is to provide a gas duct interconnecting a translatably movable oven and a relatively stationary support for the oven, which duct includes telescoping sections, one of which sections being connected with the interior of the oven and movable with the oven, and another of the sections being attached to the support so that gas may be withdrawn from the oven through the support.

It is also .an object of the invention to provide mechanism for moving the wire through the oven as the oven heats the wire and a control device for causing the oven to be removed from about the wire when the mechanism moving the wire is stopped.

A further object of the invention is to provide a guide mechanism for a wet coated wire, which mechanism includes a member engaging the coated wire and a device for supplying a constituent, or constituents similar to the, constituents of the coating on the wire for preventing deposition of the coating on the guide member.

Other and further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. l is a diagrammatic, plan view of an apparatus for coating wires:

Fig. 2 is a side view of an oven, forming a part of the apparatus illustrated in Fig, 1, for drying coating on a wire, part of the oven being broken away;

Fig. 3 is a view in section taken on line 3-3 of Fig. 2, but on a larger scale;

Fig. 4 is an end view of the oven shownuin Fig. 2;

Fig. 5 is a' view similar to Fig; 4 but showing parts of the oven in different positions; I

Fig. 6 is a view similar to Fig. 4 but showing parts of the oven in still different positions;

Fig. '7 is a view, partly in section, of a wire guide;

Fig. 8 is a top view of a wire guiding mechanism, part of the mechanism being broken away;

Fig. 9 is a view similar to Fig.8 but showing parts of the mechanism in different positions;

Fig. 10 is a view taken on line l0l0 of Fig. 9; and

Fig. 11 is a diagrammatic illustration of the control mechanism for the apparatus shown in Fig. 1.

Referring to the drawings, an apparatus 20 is shown for treating a wire 2| by wrapping insulating material about the wire, applying. wet coating over the insulation and drying the coating as the wire is passed through the apparatus. The untreated wire 21 is withdrawn from a spool 22, which spool is suitably mounted for rotation. Preferably a suitable brake is provided for maintaining a tension on the wire as the wire is unreeled from the spool. The wire first passes through a mechanism that wraps a suitable insulating material, such as glass cloth, about the wire. This type of mechanism is well known and it is therefore not described in detail. The mechanism 26 is driven by an electric motor 25, shown diagrammatically in Fig. 11. After the wire is wrapped with insulation it passes through a device 21 which deposits 2. wet coating of varnish of any suitable type on the wire. The wire next passes through two electrically heated ovens 28 arranged in tandem, which ovens dry the varnish. The wire then passes around a pulley wheel 30 and then through a second varnish applying device 3I, which device a similar to the device 21. The wire then passes through two additional oven 28 which dry the second coat of varnish. Guide devices 29 support the wire 2|.

The wire is drawn through the apparatus 20 by a. rotating 6 m 34 that is driven by the motor 25, which motor also drives the wrapping mechanism 26, The wire is looped about the drum 34 to provide traction between the drum and wire. As the wire leaves the drum 34 it is wound on a spool.35, which spool is-rotated in the proper direction by suitable-mechanism not shown. A threading device, not shown, is employed to cause the wire to be evenly disposed on the spool 35. The rate at which the wire is drawn through the apparatus 20 is such that the at times to stop the movement of the wire 2| through the apparatus 20 during the treating of sleeves 59. The outside diameters of the sleeves 59 are slightly less than the inside diameters of the sleeves BI so that the sleeves 59 telescope within the sleeve 8|. Thus the conduit 31 is connected with the interior of the tubular frame 48. Valves 82 are provided at the openings 60.

Two downwardly extending brackets 64 are attached to the frame 48 at each end thereof and a pin 65 is supported by the brackets 51 and 64 at the lower ends of the brackets. The pins 65 extend beyond the ends of the frame 48 and between fianges 66 of two vertically extending angle irons 61 two of which irons are attached to the uprights 39 and 40, respectively. The pins 65 cooperate with the flanges 66 for guiding the frame 48 vertically.

The heating portions of the ovens 28 comprise two relatively long and movable sections I0,

which sections have two surfaces that confront gether as illustrated in Fig. 3. The sections I0 the wire, and in this event it is necessary to re- 1 move the heat from the wire to prevent overheating of the varnish and the destruction of the insulating material. This can be accomplished by separating the wire and the ovens either by removing the wire from the ovens or the ovens from the wire. In the present embodiment, the, ovens 28 are removed from the wire automatically.

The ovens 28 are mounted on supports comprising inverted channel members 36 having an upright member 39 at one end and a second upright member 40 at the opposite end. The upright members 39 and 40 are braced by suitable flanges indicated at M, The member 38 cooperates with the floor to form a conduit 31 extending from one end of the member 36 to the other. One end of the conduit is closed by a wall 38. Preferably two ovens 28 are arranged end to end with the edges of theopen ends of the members 36 of the supports abutting one another for connecting the conduits 31. When the ovens are arranged in this manner, two uprights 40 will lie adjacent one another as illustrated in Fig. 2.

An elevating device 44 is mounted on each of the members 36 and each device comprises a cylinder 45 and piston 46. The piston 46 is raised by air admitted into the lower end of the cylinder 45 through a conduit I93, and the piston may be lowered in the cylinder by venting the air from the cylinder, through a conduit I94. These conduits are illustrated diagrammatically in Fig. 11.

A tubular frame 48 is mounted on the end of the piston 48 by a bracket 50. The frame 48 is formed by an inverted channel shaped member 52 and a plate 53 welded over the open side of the member 52. Skirt members 54 are also welded to two opposite sides of the channel member 52. The top wall of the member 52 is perforated as at 55, the perforated area extending substantially the length of the frame 48. The ends of the tubular frame 48 are closed by two bracket plates 51 welded to the ends of the frame.

Two openings 58 are formed in the bottom wall of the tubular frame 48 and sleeves 59 are connected around the openings, which sleeves extend downwardly. These sleeves are welded to the skirts 54. The top wall of the channel member 36 is formed with two openings 60, which openings are in alignment with the openings 58. A sleeve BI is secured around each of the openings 60 and extends upwardly to receive the are'formed of a refractory material II encased in suitable sheet metal covering 72, which covering is reenforced at the edges by angle irons 13. The bottoms of the sections I0 are reenforced by plates I4. The confronting surfaces of the sections I0 have semi-elliptical troughs 15 extending lengthwise thereof for forming an elliptical, substantially tubular opening through the oven when the two sections 10 are brought together. The walls of the troughs I5 are covered with suitable reflector sheets 16 for reflecting heat to the central portion of the opening through the oven when the oven is closed. The

ends-of the troughs 15 are closed by rectangular plates I8, which edges coinciding with the end edges of the sections 10. The confronting edges of the plates I8 are notched as at 19 to form openins in each end ofthe oven through which the wire 2| may pass while the oven is closed.

Electric heating elements are supported in the troughs'15 by rods 82, which rods are suspended in slots formed in vertical straps 83 and these straps are secured to the walls of the troughs. The heating elements 80 are connected with power mains 84 by leads 85.

The oven sections I0 are pivotally mounted on the pins 65 by brackets 88 secured to each end of the sections so that the sections may be swung outwardly with respect to one another as illustrated in Fig. 5. The brackets 88 comprise metal plates that are welded to the end plates I8. The lower ends of the brackets 88 are journaled on the pins 65. Thus the oven sections are raised and lowered when the frame 48 is raised and lowered, respectively, by the operation of the piston 48.

'One of the two brackets 88, at each end of the oven, is shorter than its complementary bracket so that the edges of the brackets may be brought together as illustrated in Figs. 4 and 6. The shortened brackets are connected to the pins 65 by metal straps 90 welded to the lower ends thereof.

The ends of the oven sections 10 are tied to the uprights 39 and 40, respectively, by links I00. The inner ends of the links are pivotally secured to the uprights by pin bearings, I02 and the outer ends of the links are connected to the sections 10 by pin bearings I03. When the frame 48 is lowered from its raised position, as illustrated in Fig. 4, the links I00 separate the sections 10, as illustrated in Fig. 5. The separation of the sections 10 forms a gap leading from the interior of the oven to the exterior thereof, which gap receives the wire as the oven is lowered from the wire. As the oven sections are further lowered the links draw the sections together to substantially close the oven, as is illustrated in Fig. 6.

Brackets I are attached to the brackets 88' above and below the links I00 and adjusting bolts I06 are threaded in these brackets for forming stops for the links I00. The links I00 engage the ends of the bolts W6 and limit vertical movement of the ovens.

An air seal i provided between the bottom walls 14 of the sections and the side walls of the frame 48. This seal comprises rubber breaker strips I08 that are secured to the bottom walls of the sections 10 by longitudinally extending angle irons I09, and .which breaker strips frictionally engage the side walls of the tubular frame 48. The angle irons I09 are secured to the plates 14 by bolts, not shown. When the ovens are in their raised or lowered positions, as illustrated in Figs. 4 and 6, respectively, the seal closes the space between the bottom of the oven sections and the perforated top wall of the frame 48.

Gases produced by baking of the varnish on the wire 2I are removed from the oven by a fan III] that is connected by suitable conduits, not shown, to the ducts 31 formed by the support members 36 and the floor. As the fan is operated air is drawn through the openings between the oven sections 10 and into the tubular frames 48 through-the apertures 55. The air carries the gases from the ovens through the sleeves 51 and 6I'into the conduits 31. The fan H0 then exhausts the air and gases into the atmosphere. Preferably the fan H0 is operated during the time that the ovens are energized by an electric motor II I.

Referring to Fig. 7, one of the wire guide devices 29 is. shown in detail. The device 29 includes a supporting plate H4 and a roller H5 is mounted on the plate II4 by a suitable bearing II 6, which roller supports the wire 2I passing through the apparatus 20. The plate H4 is adapted to be attached to the uprights 39 or 40 of the ovens 28. The periphery of the roller H5 is maintained moistened with a suitable thinner that forms a constituent of the varnish that is applied to the wire 2I at 21 and 3I so that varnish on the wire passing over the roller will absorb the thinner and not adhere to the roller. This thinner is applied to the roller through a pipe I I8 mounted in an opening through the plate H4, which pipe is connected at one end to a reservoir I and the other end opens into a trough I2I. The liquid thinner is placed in the reservoir and is fed to the trough I2I through the pipe H8. A suitable wick I22 is placed in the trough I2I and engages the lower edge of the roller for transferring thinner to the roller as the roller is rotated by the wire 2I.

The pulley wheel 30 is mounted on mechanism that moves the wheel 30 in the direction of expansion and contraction of the wire 2|, caused by changes in temperature of the wire. This mechanism includes a base I25 that is attached to a wall or other suitable support, which support is not shown. A U-shaped bracket I26 is secured at its open ends to the base I25. Two members I21 and I28 are pivoted together at I29 to form a hinge. The free end of the member I21 is attached to the yoke of the member I26 and a shaft I30 is attached to the free end of the member I28 by brackets I3I. The pulley wheel 30 is rotatably mounted on the shaft I30 and is supported by a suitable anti-friction bearing I32, disposed between the upper bracket I3I and the This support I31 permits the cylinder to swing.

The rod of the piston I36 extends through openings in the members I21 and.I28 andis pivotally connected to the shaft I30. 'Air, under pressure, is admitted to the left hand end of the cylinder I35, as viewed in Fig. 11, through pipe I38 andto the right-hand end of the cylinder through a pipe I39. When airis forced into the right hand end of-thecylinder I35 the piston moves the wheel-30 in the direction of expansion of the wire 2 I, as is illustrated in Fig. 9, and when air is forced into the lefthand end of the cylinder I35 the pistonimoves the pulley wheel 30 to the position shown in Fig. 8, or in the direction of contraction of the wire 2I. The flow of air to the cylinder I35 is controlled by valves operated simultaneously with the raising and lowering of the oven sections 10. These valves are described hereinafter. The travel of the piston I36 in one direction is equal to the expansion of the portion of the wire 2I heated by two of the ovens.

The periphery of the pulley wheel 30 is maintained moist by varnish thinner, applied by a suitable device I40, which device may be constructed similarly to the devices 29.

Referring to Fig. 11, the control circuits for the apparatus 20 are illustrated diagrammatically, the circuits being deenergized. Electric current is supplied to the apparatus by two mains I46 and I41 through a suitable double pole switch I48, which switch is closed manually. The heater elements of the ovens 28 and the motor I I I for the fan H0 are connected in parallel circuits and are energized when the switch I48 is closed. The circuit for the heating elements 80 is established from main I46 through switch I48, wires I49, I50, I5I, elements 80, wire I52 and switch I48 to main I41. i

The fan motor III is energized by current traversing wires I49 and I50 to one side of the motor, and wires I53, I54 and I52. Thus the fan H0 will operate during the time the oven heaters are energized.

The motor 25 for driving the wire wrapping mechanism 26 and the drum 34, is adapted to be energized by closing any one of the normally open switches I56, which switches may be located at convenient points along the apparatus 20. The closure of any one of the switches I56 establishes a circuit from wire I49 through the closed switch I56 to wire I51, coil I58 of relay I59, wire I60, normally closed switches I6I, wire I62, coil I63 of relay I64, and wires I65, I54 and I52. The relay I59 closes a switch I66 to complete a holding circuit around the switches I56. This holding circuit is established from wire I49 through wires I61 and I68, switch I66, wire I69 and coil I58. The relay I64, when energized, opens switch contacts I10 and closes switch contacts "I for establishing a circuit from wire I68 through wire I14, switch contacts I1I, wire I15, coil I16 of relay I11 and wires I18, I54 and I52. The relay I11, when energized, closes the switch I19 for completing the circuit for the motor 25, which circuit includes wire I49, motor 25, wires I80, I18, I54 and I 52. Thus the motor 25 is energized to cause the wire 2| to be moved through the apparatus 20 and to drive the mechanism 26 to wrap irisula tion on the wire.

The closing of the contacts I1I also establishes a circuit from wire I through wire I8I-,

through the coil I82 of a magnetic valve 183 1 I92, which air passes into the lower end of the cylinders 45 through pipes I93 interconnecting themanifold I92 and'the cylinders. Conduits I 94' interconnect the cylinders 45 and an exhaust manifold I95. The manifold I95 is closed by a magnetic valve I96, which valve is closed while the contacts I10 are open. The pistons 46 raise the oven sections 110 so that the sections are enclosed about the wire 2 I. Air: from the manifold I92 is also forced into the right hand end of the cylinder I35, as viewed in'Fi'g. 11, through a throttling valve I98 and pipe I39 for causing the pulley wheel 30 to be moved in-thedirection of expansion of the wire. Air is vented from the left side of the piston I36 through the pipe I38, throttling valve I99, pipe 200 and through a. two-way valve I, which valve is positioned to discharge air from pipe 200 to the atmosphere. The air pressure supplied through the conduit I90 maintains the ovens 28 in .their raised positions, as illustrated in Figs. 2, 3 and 4.

In case 'it is desirable to deenergize the motor for any reason, any one of the switches I6I maybe opened for breaking the circuits'of the relays I59 and. I64. This deenergizes the relay I11 and opens the motor switch I19. The coil I82 of the valve I83 is also deenergized and the valve is closed. The pistons 46, however, will remain in their raised positions because the exhaust manifold I95 is closed by the valve I96.

When the relay I64 is deenergized, the contacts I10 are closed and a circuit is established through the coil 2I0 for a time delay relay 2I I, which, circuit is established throu h the '-wires' I61, 2I2, coil 2I0, wires 2I3 and I54. After a predetermined time period has elapsed, the relayv 2I I closes the switch 2I4 for completing a circuit through wires I61, 2I5, 2I5, coil 2I1 of valve I96, wires 2I8 and 2I9, switch 2I4, wires 2I3, I54 and I52. The coil 22I, of the magnetic valve 20I ,is connected in parallel circuit with coil 2I1 as it is connected to thewires 2I5 and 2I9.

The energization of the coil 2I1 of the valve I96 opens the exhaust manifold I95 to vent the air from the cylinders 45 for causing the ovens 28 to be lowered by gravity to the position shown in 6. Simultaneously, the energization of coil 22I of valve 20I, causes the twoway valve to rotate to a position in which the port thereof, leading to the atmosphere, is closed and another port connects a pipe 223 to pipe .290. Pipe 223 is connected to pipe I90, and air is now admitted to the left side of the piston I36 through the throttle valve I99, to cause the pulley wheel 30 to be moved in the direction of contraction of the wire when the oven sections.10 are moved from about the wire. Air is vented from the right hand side of the piston I36 through pipe I39, valve I98, manifold I92, pipes I93, cylinders 45, conduits I94 and manifold I95.

The speed of movement of the pulley 30 in either direction is controlled by the flow of air through the throttle valves I98 and I99, and this speed is computed to correspond to the rate of expansion and contraction of the wire, during the heating and cooling thereof, so that the wire is maintained slightly taut at all times. Also, by causing the pulley 30 to move in the .direction of the contraction of the wire 2I, the wire .will not be stretched away from the wrapping mechanism 26 after the mechanism has stopped. Otherwise, when the'operation of the wire coating apparatus is temporarily halted, a gap would'be formed in the insulation wrapping on thewire, due to the wire, on cooling, stretching. away from the inoperative wrapping mech anism.

The wire wrapping mechanism 26 and drum 34 will, coast for approximately six 'seconds, for example, after the motor 25 is deenergized, therefore the'time delay relay 2I0 is adjusted so that the ovens will not be lowered from about the wire 2I until the wire is substantially stopped.

' It is apparent that fluid other than airmight be used to operate the pistons 46 in the'cylinders 45 or the piston I36 in the cylinder I35.

While the form of embodiment of the present invention as herein disclosed constitutes a pre-' ferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

We claim:

1. In combination, an oven including two elongated sections, said sections being adapted to form a heating chammr when adjacent one another, said heating chamber being open along one'side thereof; means for moving one of said sections relative to the other for openim said chamber; an elongated hollow member extendin along said one side of the chamber formed by said sections, said hollow member having an opening in registration with the opening in said chamber for forming a passage between the chamber and interior of said hollow member; a breaker strip carried by said one section, said breaker strip beingarranged to frictionally en-' gagea side of said hollow member when said one section is moved adjacent the other section for forming a heating chamber; and means for withdrawing gas from said hollow member.

2. In combination, means forming an oven having an inlet opening and an outlet opening for the passage of a wire or the like through the oven; mechanism for moving the wire or the like through said openings; power operated means for driving said mechanism, said mechanism being adapted to coastto stopping position after the power operated means is rendered ineffective; mechanism for causing relative movement to be imparted between the wire and the oven for disassociating the entire wire from heat transfer relation with the oven; and control apparatus for said-mechanisms, said apparatus including means forrendering the power operated means ineffective, time delay'means for delaying the starting of the second mentioned mechanism until the first mentioned mechanism is substantially stopped, and means rendered operative by the first mentioned means of the control apparatus for rendering the time delay means operative.

3. In combination, means forming an oven having two sections, said sections cooperating to form an elongated passage having heat radiating walls, said passage beingadapted to receive a wire or the like extending longitudinally through the passage; mechanism for moving the said wire or the like through the ,passage longitudinally; mechanism for moving said sections -laterally with respect to the wire for disassociating the wire from heat transfer relation with the oven;

and control apparatus for said mechanisms, said apparatus including means decreasing operation of the first mentioned mechanism and after a predetermined time after said decrease, means rendered operative by the means of the control apparatus, for rendering the second mentioned mechanism operative.

4. In combination, an oven comprising a plurality of complementary sections; and mechanism for bodily moving the oven from one position to another position and for moving the sections first away from one another and then toward one another while the oven is bodily moving from said one position to said other position, said mechanism including a pivot for one section, a stationary support forming a stationary guideway for said pivot means for moving said pivot along said guideway from one position to another position, and means including a guide member having a part fixedly associated with said support and a part fixedly associated with said one section for causing swinging movement to be imparted to said one section from and toward said other section about said pivot as the pivot moves along said guideway from said one position of the pivot to said other position thereof.

5. In combination, an oven comprising a plurality of complementary sections; and mechanism for bodily moving the oven from one position to another position and for moving one of the sections first away from and then toward another section while the oven is bodily moving from said one position to said other position, said mechanism including a pivot for said one section, a support for said pivot, means for moving said pivot in a straight line from one position to another position, a link connected at one end of said one section and a pivot for the other end of said link, a support for said second mentioned pivot, the first mentioned pivot being movable relative to the second mentioned pivot, said link swinging said section from and toward the other of said sections when the first mentioned pivot moves in a straight line from said one position thereof to said other position thereof.

6. In combination, an oven comprising two complementary sections; means for pivoting said sections for permitting said sections to be swung relative to one another; a link connected at one end to one of said sections; a second link connected at one end to the other of said sections, the opposite ends of said links extending towardone another; means for fixedly pivoting said opposite ends of said links; and means for moving the first mentioned pivoting means relative to the second mentioned pivoting means for causing said links to, be rotated about the pivoting means therefor in opposite directions for swinging said sections relative to one another.

7. In combination, a horizontally elongated oven having a heating chamber, said heating chamber being open'along one side thereof; a horizontally elongated frame supporting said oven, said frame forming an elongated chamber, said frame chamber being open along one side thereof, the openings in said chambers registering with one another; an elongated supporting base for the frame arranged below and parallel with the frame, said base forming a horizontally disposed tubular chamber; an open top tube extending upwardly from the base toward the frame and communicating with the interior of the base chamber; an open bottom tube extending downwardly from the frame and communicating with the frame chamber, said tubes telescoping with one another; mechanism supported by the base for moving the frame vertically; and means for exhausting gases from the base chamber.

NATHAN J. GREENE. GEORGE C. REESE.

CERTIFICATE OF CORRECTION. Patent No. 2,525,950. August 3, 191g.

NATHAN J. GREENE, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, sec- 0nd column, line 56, for "which edges coinciding" read --which plates have edges coinciding-; line 59, for "openins' read --openings-; page 1;, first column, line 14.1, for the word "for" read -of-; page 5, first. columh, line 18, claim 14., after "pivot" insert a semicolon; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of September, A. D. 1914.5.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

